I've reverted the partitioning scheme back to GPT. Using fdisk I defined the primary partitions sda1 and 2 as EFI and Swap respectively. The remaining partitioning was done within the installer. Thanks Pascal.

[snip]>>Installing to a PV is a fairly straightforward matter. Here is a worked>out example of installing to a microSD. It should work pretty much the>same for any other type of block device.>>Manual partitioning (done on an existing Stretch installation with>gparted) shows the following from fdisk -l:>>Device Boot Start End Sectors Size Id Type>/dev/mmcblk0p1 2048 4095 2048 1M 83 Linux>/dev/mmcblk0p2 4096 4198399 4194304 2G 82 Linux swap />Solaris>/dev/mmcblk0p3 4198400 124735487 120537088 57.5G 5 Extended>/dev/mmcblk0p5 4200448 54532095 50331648 24G 8e Linux LVM>/dev/mmcblk0p6 54534144 121643007 67108864 32G 8e Linux LVM>/dev/mmcblk0p7 121645056 124735487 3090432 1.5G 83 Linux>>Partitions p5 and p6 are lvm physical volumes.>>I also, in emulation, created volume group "debian9-vg" on p5 and a>logical volume "root" on debian9-vg and formatted it as ext4. It mounts>normally on the host and (from a shell prompt) with the installer. I did>not leave it mounted.>>The view from the installer partitioner shows essentially the same>thing. From an installer root prompt, lvm commands appear to work>normally, and I created additional LVs swap_1 (2G), tmp (512M), var>(2G), and home (4G), leaving 7.5G free.>>>From the installer (partitioner):>>All disk partitions, and all LVM logical volumes are shown.>>Choosing "Configure the Logical Volume Manager leads to the choice to>format p2 as swap; I did that, and got a frame showing the two PVs (one>used and 1 free), 1 VG, and the 5 LVs and options to "Display>configuration details," "Create volume group," "Create logical volume,">"Delete logical volume," "Extend volume group," and "Finish.">>Display showed the unallocated PV and the debian9-vg with its 5 LVs.>Creating a VG (debian9t) and LVs on partition p6 with the installer>partitioner also works. However, the LVs are created with sizes powers>of 10 instead of 2 (e. g., 1M=1000K=1000000 bytes instead of>1M=1048K=1048576 bytes). I prefer the powers of two, so from a shell>prompt I removed and recreated the LVs on debian9t to match those on the>debian9-vg created earlier.>>Note that the partitioning can be done from either another (reasonably>up to date) debian system, including a live CD, I expect, or the>installer, and using either the partitioner or lvm commands from an>installer shell prompt. The partitioner then showed and allowed>configuration of all volume groups and logical volumes. It is necessary>to be careful to not use any partitions, volume groups, or logical>volumes that contain data you want to keep, although the partitioner>will warn about using existing resources.>>>From this point, I used the installer partitioner to configure, format,>and specify mount points for LVs associated with the debian9-vg volume>group. The installer correctly identified the root LV, already formatted>as ext4, and offered the option of not reformatting it.>>The installation went forward normally, and at stage 1 completion I>chose a relatively local mirror. I did not see the deb.debian.org>redirector listed, which might be a nice thing.>>Tom Dial>

Finishing with the installer, the GPT scheme looks like this:

NAME FSTYPE MOUNTPOINT

sda

├─sda1 vfat /boot/efi

├─sda2 swap

├─sda3 LVM2_member

│ ├─debian8--vg-root ext4 /

│ ├─debian8--vg-home ext4 /home

│ ├─debian8--vg-tmp ext4 /tmp

│ └─debian8--vg-var ext4 /var

├─sda4 LVM2_member

├─sda5 LVM2_member

├─sda6 LVM2_member

└─sda7

sr0 iso9660

The installer says that installation is complete and reboots, but this is not successful: